Radiation segmentectomy for treatment of hepatic oligometastases greater than 3 cm

The effectiveness of percutaneous thermoablation as curative treatment of hepatic oligometastases greater than 3 cm can be limited by the ability to achieve adequate ablation coverage. Radiation segmentectomy (RS) using yttrium-90 (Y90) microspheres is an established treatment and potentially curative for hepatocellular carcinoma (HCC) up to 8 cm. This study evaluates the safety and effectiveness of RS for secondary liver tumors larger than 3 cm.

A retrospective review at a single institution was performed from December 2017 to February 2024 to include patients treated with transarterial radioembolization (TARE) for liver metastases using glass Y90 microspheres. RS was defined as a target dose > 200 Gy to no more than two liver segments. The following outcomes were retrieved: overall survival (OS), radiologic response, progression-free survival (PFS), adverse events, and 3-month serum toxicity.

A total of 14 patients (mean age: 64.2 ± 18.5, M:F = 5:9) with secondary liver tumors (mean diameter: 4.7 ± 1.4 cm; single hepatic lesion: 57.1 %[8/14]), including 5 colorectal cancer (35.7 %), 2 renal cell carcinoma (14.3 %), 2 uveal melanoma (14.3 %), 2 adenoid cystic carcinoma (14.3 %), 1 pancreatic adenocarcinoma (7.1 %), 1 endometrial carcinoma (7.1 %), and 1 tonsillar adenocarcinoma (7.1 %). The mean segmentectomy dose was 352.6 ± 149.1 Gy. Response rate and disease control rate were 42.9 % (6/14) and 85.7 % (12/14), respectively. The 1-yr and 3-yr target tumor response rates were 51.4 % (95 %CI: 21.9-74.8 %) and 34.2 % (95 %CI: 7.1-64.9 %), respectively, with a median PFS of 16.3 months 95 %CI: 5.4 months-not reached). The 1-yr and 3-yr OS were 80.8 % (95 %CI: 42.4-94.9 %) and 40.4 % (95 %CI: 9.8-70.2 %), respectively, with a median OS of 24.3 months (95 %CI: 8.9-not reached). One patient developed grade 3 thrombocytopenia, requiring holding of systemic treatment (7.1 %). No additional grade 3 or above adverse events occurred.

Preliminary results suggest that RS is a feasible treatment option for secondary liver tumors > 3 cm with few major adverse events.